Peter Townsend
1914-1995. War veteran, Princess Margaret and he wanted to marry in 1955, but - after pressure from the Church, parts of the media, politics and the Royal family - Margaret decided against it.

Peter Wooldridge Townsend was born in 1914. He distinguished himself as a pilot in the Royal Air Force and had the rank of Group Captain. Later he worked as the Queens equerry. Princess Margeret is said to have had a crush on him since the first time she saw him on a tour to South Africa. She was only 14 years back then and he was already married and had two children. He later got divorced from his wife. In June 1953, during the coronation of Queen Elizabeth, the press observed Margaret brushing a hair from Group Captain Townsend`s uniform. From that moment on the public was also interested in their affair. The couple had already told the Royal family about their relationship and their marriage plans. Since amrgaret was not yet 25 years of age, her sister, the Queen had to consent to their marriage. this is staed in the Royal Marriages Act of 1772. The main problem however was that Peter Townsend was divorced. So the Church, as well as the Parliament were against the marriage. Townsend was sent to Bruessels by the Queen`s private secretary Tommy Lascelles. When he came back two years later Margeret had turned 25 and could decide herself, without the consentof her sister. She finally decided against the marriages and geve a brie statement to the press announcing the end of her relationship.
' I would like it to be known thet I have decided not to marry Group Captain Townsend.
I have been aware that, subject to my renouncing my rights of succession, it might have been possible for me to contract a civil marriage. But, mindful of the Church`s teaching that Christian marriage is indissoluble, and consious of my duty to the Commonwealth, I have resolved to put these considerations before any others. I have reached this decision entirely alone, and in doing so I have been stregthened by the unfailing support of Goup Captain Townsend.'
On 1959 Peter Townsend married Marie Luce Jamagne and had two children with her. He lived near paris and wrote six book, one of them his autobiography "Time and Changere" (1978). There he wrote about the end of his relationship with Princess Margaret: "She could have married me only if she had been prepared to give up everything - her position, her prestige, her privy purse, I simply hadn´t the weight, I knew it, to counterbalance all she would have lost." He died in 1995.
Sources:
http://news.bbc.co.uk/onthisday/hi/dates/stories/october/31/newsid_3202000/3202307.stm
http://www.nytimes.com/1995/06/21/obituaries/peter-townsend-dies-at-80-princess-margaret-s-love.html